Editor's take: The iPhone 12 and iPhone 12 Pro have far more in common with each other than previous generations did. Does that make it harder for Apple to justify the price difference?
During their yearly iPhone teardown, the repair experts at iFixit discovered that the 12 and 12 Pro share a common internal design. Their preliminary testing has found that the screens appear to be interchangeable, despite being rated for different levels of brightness, and they believe that the batteries and extra components like the taptic engine are completely identical between the two models.
(Disclaimer: don't try and swap parts between devices, Apple will brick your phone.)
Last year's models, the 11 and 11 Pro, were different in size and material and design. Although the 11 was larger than the Pro, this was not a premium feature: the additional space made the design simpler, and thus cheaper to build. The 11 Pro required a more advanced screen technology (OLED vs LCD) to be thin, bezel-free, and efficient, and it also had a more complex battery design to improve its density. The two devices thus required an entirely different internal structure.
As you can see in these x-ray images, that's no longer the case for the 12 and 12 Pro.
The iPhone 12 series has brought the flagship and second-tier models much closer together. The only physical improvements the 12 Pro has is the stainless steel rim, versus an aluminum one, and the extra telephoto camera and LiDAR sensor. The rims are identical in shape, so there's no real difference there, and in the spot where the additional photography implements would go the 12 has empty space.
Apple's reasoning for making the devices so similar probably comes down to price. It's been reported that the new 5G components are very expensive, and Apple may have needed to simplify their assembly lines to balance out the additional components cost.
From a consumer perspective, though, they've simply made the vanilla iPhone 12 a more appealing product. Although the difference in price between the base models of the 12 and 12 Pro is $200, if they're both configured with 128 GB of storage (the 12 Pro's minimum), the price difference shrinks to just $120. So the question is: is a brighter screen, stainless steel rim, a telephoto lens, and an extra sensor worth $120 extra?